1. Field of the Invention
The present invention relates in general to monitors, and more particularly, to a method and apparatus for providing cathode output scaling so as to provide optimization of the cathode output.
2. Description of the Related Art
Cathode ray tubes ("CRT") are typically employed in electronic display systems, such as a television receiver or a display apparatus including a CRT numerical display. Each color CRT consists of three electron guns (a red, a green and a blue electron gun) and a phosphor screen that is located inside an evacuated glass envelope. Each electron gun generates a beam of electrons that is accelerated towards the screen by a positive anode voltage.
In CRTs, temperature drifts within the evaluated glass envelope result in image luminance distortion or the alteration of the white balance. Luminance indicates the amount of light intensity which is perceived by the eye as brightness, while the control of luminance is termed "white balance" since white light may be considered and provided as a mixture of the red, green, and blue primary colors in the proper proportions.
To reduce temperature drift, the CRTs are typically subjected to a process known as "aging" during manufacture. This process involves the warming up of cathode ray tubes ("CRT") to facilitate testing of circuitry and adjustment of various display parameters such as color convergence and picture geometry. Conventional aging techniques typically involve applying a single input voltage to each of the three electron guns to cause each electron gun to generate the corresponding luminance. However, since each electron gun generates a different color, each of the electron guns also operates to provide an optimum output at a different input voltage. This input voltage varies from one electron gun to another. Thus, although one of the three electron guns may be operating at a maximum level, the remaining two electron guns are not.
Accordingly, there is a need in the technology for a method and apparatus for providing suitable input voltages to each cathode in a cathode ray tube so as to provide optimization of the cathode output for each electron gun in a cathode ray tube for the aging process during manufacture.